Conventional power nailers or staplers as disclosed in U.S. Pat. No. 6,170,729, U.S. Pat. No. 6,427,896 and publication number 2003/0019901 include a safety device and an adjustable device installed close to the nose of the nailer. However, it is experienced that the safety device is composed of a plurality of links and the adjustable device is located at the middle portion of the safety device, so that the links shake when operating the adjustable device. The adjustment cannot be precisely completed due to the shaking. Besides, the adjustable device is located away from the handle or the trigger so that the user has to use one hand to hold the handle and operate the trigger, and the other hand to operate the adjustable device. Furthermore, the adjustable device and the safety device are secured correspondingly so that different safety devices or adjustable device cannot be replaced.
The present invention intends to provide an adjustable device that is located close to the trigger and connected to the safety device by a retaining member which allows different types of safety devices or adjustable devices to be connected with each other.